Foam producing apparatus



June 13, 1961 G. DION-BIRO FOAM PRODUCING APPARATUS 2 Shees-Sheet 1 illl|l||l |||1| lllllllllr lll l|| lll |ll lllll ll ll lill lll llll Filed JAlne 19, 1958 June 13, 1961 G. DION-Emo FOAM PRoDUcING APPARATUS 2 Sheets-Sheet 2 Filed June 19, 1958 f i E A W., W, M

United States Patent i 2,988,151 FOAM PRODUCING APPARATUS Guy Dion-Bim, 33 Rue Louvois, Chaville, France Filed June 19, 1958, Ser. No. 743,101 Claims priority, application France June 21, 1957 3 Claims. (Cl. 169-14) The present invention relates to an apparatus for producing chemical foam for extinguishing tires.

It is already known to produce by a chemical process a foam utilized in tire-extinguishing apparatus by causing a basic ingredient and an acid ingredient to contact each other. According to a prior proposal these two ingredients are housed in two containers disposed concentrically or side by side, this assembly being handled in a particular manner at the time of its actual use, for example, by turning it upside down, whereby the foam develops due to the mixing of the two ingredients. A hose conveys the foam to the spray nozzle.

This method of operation has, however, serious inconveniences.

A rst inconvenience -is in that the expansion of the mixture thus obtained is relatively moderate. Thus, when the theoretical importance of the expansion of the mixture is controlled in a laboratory by means of a special apparatus called Spulmometen or even by means of a graduated glass vessel or cylinder, it is observed that the best mixtures give an expansion of the order of fifteen times the initial volume of the two ingredients. This is due to the fact that only small quantities of the initial ingredients are actually present, so that a satisfactory mixing effect is not obtained.

However, in practice, that is, when a commercial application of the process is effected, the expansion obtained is considerably smaller. In fact, as the two ingredients are precipitated into each other within a Vessel of substantial volume, of the order of to 50 litres, and even 100 litres, the rst particles of the two ingredients which meet therein react exactly as desired, but then, as the process continues, one of the ingredients neutralizes the other, so that the reaction of these ingredients remains incomplete. Under these conditions, the expansion of the chemicals to a foam produced on a commercial basis is at the best of the order of seven times the initial volume of the ingredients.

Consequently, the hitherto utilized method of producing chemical foam gives an unsatisfactory result, as the expansion is relatively moderate, due to the incomplete reaction of the ingredients.

Another inconvenience of this conventional method is that even if the operator needs but a small quantity of foam, for example for extinguishing a small, well-defined iire, it is nevertheless necessary to mix completely the two ingredients contained in the two reservoirs or like vessels. Under these conditions, it is definitely impossible to stop the reaction of the ingredients, so that they react completely and a substantial waste of relatively costly products follows.

A third inconvenience characterizing this conventional method is that the foam is produced in close vicinity of the reservoir containing the reagents so that the foam must subsequently be conveyed through a hose to the projection or spray nozzle. However, as this foam solidities quickly, it is not possible to transport it along lines of relatively great length.

It is an important object of the present invention to avoid these various drawbacks, notably by increasing to a considerable degree the expansion of the mixture produced. This invention is also concerned with the production of only the desired quantity of foam, the production of foam being discontinued at will by stopping, when desired, the reaction of the two initial ingredients. It

, ZQSS Patented Jurre 13, 1961 ice is another object of this invention to produce foam in close vicinity of the place of its actual use, that is, of the spray moule.

To this end, the present invention provides apparatus for producing chemical foam which consists in transferring separately in two diiierent conduits and under a moderate pressure the two initial foam-producing ingredients, that is, the basic ingredient and the acid ingredient, for example aluminum sulfate diluted in water and sodium bicarbonate also diluted and in admixture with an emulsiier, to a foam-generating vessel located in close proximity of the spray nozzle, and causing the two ingredients to be discharged into this vessel at a suitable velocity and finally causing the particles of these ingredients to impinge against each other, so that it is only when the two ingredients meet each other at a predetermined velocity that foam is produced with a considerable degree of expansion.

The velocity at which the two ingredients are caused to penetrate into the foam-generating vessel ranges preferably from 4.5 meters/sec. to 8 meters/sec., as it has been determined by actual experiments that velocities of this order constitute a determinant factor for ensuring an optimum reaction of the particles of both ingredients when they hit one another, thus providing a maximum swelling of the foam. The novelty of the apparatus of this invention lies therefore essentially in that it produces chemical foam by causing the jets of the acid and basic ingredients to meet each other at a predetermined velocity, thereby producing not only a simple mixture of these ingredients but also their intermixing (that is, a mixing attended by a dynamic action) in a closed chamber of a vessel located in close proximity of the spray nozzle.

It is another object of this invention to provide an apparatus for producing chemical foam, which is characterized in that it comprises two separate reservoirs or sources containing the initial ingredients, a compressedgas `cylinder connected to the two reservoirs and adapted to discharge their contents under a moderate pressure, two separate conduits leading from one and the other of the reservoirs to a foam-generating vessel, this vessel being provided with a spray nozzle equipped with a valve, the combined cross-sectional area of the oriiices through which the two conduits lead into said foam-generating vessel and the cross-sectional area of the discharge orifice at the outlet of the spray nozzle being so determined, with due consideration for the degree of swelling of the foam, as to obtain the desired velocity of the two jets of ingredients as they are projected into the vessel, this velocity being preferably of the order of from 4.5 meters/ sec. to 8 meters/ sec.

An embodiment of the apparatus of this invention will be described with reference 4to the attached drawings forming part of this specification. in the drawings:

FIGURE l is a diagrammatic partsectional View of the entire apparatus;

FIGURE 2 is an axial section showing the foamgenerating vessel on a larger scale; and

FIGURE 3 is a section taken along the line III-lll of FIGURE 2.

The apparatus illustrated in the drawings comprises two reservoirs or sources 1, 2 containing respectively the acid liquid ingredient 1a and the basic liquid ingredient 2a. Considering the difference in the volumes of these two ingredients which are to be delivered to produce a convenient foam, these reservoirs have different capacities, preferably in the proportion of 1:5. The liquids contained in these reservoirs may be of any acid and basic types suitable for producing a tire-extinguishing foam by chemical reaction with each other, as will readily occur to anybody conversant with the art. Thus,

these foam-producing ingredients may have the following composition:

Acid liquid-900 grams of aluminum sulfate diluted in one 'litre of water.

Basic liquid- 656 grams of sodium bicarbonate in admixture with 94 grams of an emulsier, this mixture being diluted in seven litres of water.

The apparatus further comprises a small cylinder 3 containing a compressed gas and equipped with a stopcock 3a.

This cylinder is connected to the larger reservoir I2 by a preferably flexible conduit 4 having inserted in an intermediate section a pressure-reducer or like device 5 for adjusting the expansion of the gas issuing from the cylinder 3 in the receiving reservoir 2. Another conduit 6 connects the reservoir 2 with the smaller reservoir 1 to constitute a pressure-equalizing device between the two reservoirs. This pressure may be adjusted by means of the device 5 and maintained at a constant, preferably moderate value of the order of l to 4 kg./cm.2 (14 to 57 p.s.i.).

The conduit 6 leads into a hollow plug 7 closing the reservoir 1; through this plug 7 and in fluid-tight relationship thereto extends a tube 8 of which the inner end is positioned near the bottom of the reservoir 1. Connected to the outer end of the tube 8 is a flexible conduit 9 leading to a T fitting 10 connected on the other hand to another tube 11 extending through the top wall of the reservoir 2 to a point situated in close proximity of the bottom of this reservoir. More particularly, the conduit 9 is connected to a socket 12 extending coaxially within the fitting this socket communicates with an axial passage 13a formed in a coupling 13 provided at the opposite end of the fitting 10. The central branch 10b of the T fitting 10 communicates with the tube 11 and the inner space of this fitting communicates with a plurality of peripheral longitudinal passages 13b formed in the coupling 13 around the axial passage 13a, to constitute an arrangement of the type shown in FIG. 3 with reference to the foam-generating vessel, as will be explained presently.

Threaded on the outer surface of the coupling 13 is the end of a iiexible conduit 14, whereby the latter communicates directly with the inner space of reservoir 2. This conduit surrounds another flexible conduit 15, one end of which is fitted on the projecting end of the axial passage 13a of coupling 13, as shown.

The inner flexible conduit has obviously a smaller cross-sectional area than the conduit 14 through which the basic ingredient is conveyed, the ratio of these crosssectional areas being approximately 1:5 to take due consideration of the difference between the volumes to be delivered therethrough.

Both iiexible conduits 14, 15 lead into a closed space of an elongate vessel 16 constituting the foam-generating chamber. These conduits are connected to the corresponding tubular components of a tube 17 carried by one end of this vessel, somewhat like the connection of the tube 13. Thus, this coupling 17 comprises a first coniponent 17a whose tubular wall projects outside the inner and outer ends of the coupling, and has threaded on its outer end the aforesaid conduit 15, as shown. On the other hand, this tube 17 has a second component 17b defining six peripheral passages disposed at spaced angular intervals around the first component 17a axially therewith, and the outer conduit 14 is threaded on the outer wall of the tube 17, as shown. The ratio of the area of the orifice in the component 17a to the combined area of the orifices in the component 17b is preferably of the order of 1:5, also in order to keep due account of the difference in the volumes of the ingredients to be delivered to the vessel 16. It will be noted that the components 17a, 17b of the tube 17 actually constitute the discharge ends of the conduits 15, 14, respectively.

The vessel licomprises, in axial alignment with,.and at an adjustable relative spacing from, the components 17a, 17b, a deiiector means 18 formed with a concave annular surface portion located opposite the second component 17b and also with a convex central projecting portion 18a facing the first component 17a and arranged in axial alignment with the latters orifice. This deflector 18 is carried by a spindle 19 slidably mounted in a fixed socket 20 rigid with a plug 21 closing the end of the vessel 16 which is opposite to the end carrying the tube 17. The spindle 19 is formed with an outer extension carrying manually operable means in the form of a knob 22; on the other hand, it comprises a screw-threaded portion engaging a tapped portion of the fixed socket 20, so that when the operator rotates the knob 22 the deflector 18 is moved in one or the other axial direction to change its spacing from the inner end of the component 17a. In this manner adjusting means for the spacing of the deflector means from the conduit are provided. Deiiector means 18 are arranged in vessel 16 transverse to the direction of the axis of the first component 17a and facing the same. i

In the vicinity of the plug 21 the wall of the vessel 16 carries an outlet pipe 23 communicating with the interior of the chamber. Fitted on the outer end of this outlet pipe 23 is a rigid tube 24 constituting the body or support of a spray nozzle, the outer end of this outlet means 24 leading to a valve 25, for example of the faucet type, having connected on its outlet side the spray nozzle 26 proper. The vessel 16 and its outlet pipe 23, the tube 24 and spray nozzle 26 constitute a rigid assembly that can be held with the hands for directing the jet of foam against the tire, a gripping handle 27 being provided for this purpose.

According to an essential feature of this invention, the ratio of the aggregate cross-sectional area of the orifices through which the components 17a and 17 b communicate with the vessel 16 on the one hand, to the cross-sectional area of the discharge end of the spray nozzle 26 on the other hand, is determined with due consideration of the degree of foam swelling to be obtained, whereby the velocity at which the two acid and basic ingredients penetrate into the vessel 16 may range from 4.5 meters/sec. to 8 meters/sec. (14.5 ft./sec. to 26 ft./sec.), this velocity being for example preferably of about 5 meters/ sec. This velocity of iiow constitutes the optimum rate at which the particles of the two ingredients will meet to determine the aforesaid intermixing (that is, an admixture attended by a dynamic effect) of the particles of the ingredients and therefore an optimum reaction yielding a foam having a considerable degree of expansion. If the velocity of the particles of the ingredients, when they meet each other, is higher than 8 m./sec. (26.4 ft./sec.) or lower than 4.5 m./sec. (14.5 ft./sec.), the swelling decreases considerably. Since, according to the method of this invention, the reaction takes place through the relative meeting of the jets of the two ingredients with the aforesaid dynamic effect, all the particles of these two ingredients will react completely, as contrasted with what is observed when, according to the conventional practice, the foam is produced by causing the whole of two ingredients to mix together in a common space.

Without limiting the scope and eld of this invention and by wayr of indication only, the following orifice sizes may be suggested:

Orifice of the component 17a-diameter 11 millimeters;

Each of the six passages in the component 17b-diameter 10 millimeters;

Outlet orifice of spray nozzle 2li-diameter 24 millimeters.

Of course, this is only a mere example, but in any case the passage formed in the stopcock 25 should preferably be of the straightiiow type, that is, without any throttling means.

The swelling of the foam produced with the method of Athis `invention may be of the order of thirty times the initial volume of the two ingredients, if the theoretical swelling of these ingredients is 35 times their initial volume, whereas with the conventional method the swelling obtained in practice is of the order of seven times the initial volume. With the method of this invention the maximum volume of foam is obtained in the minimum time. It may be pointed out that the pressure utilized for forcing the two ingredients into the vessel 16 is relatively moderate, of the order of l to 4 kg./cm.2 (14 to 57 p.s.i.) as already stated. However, with this method and by utilizing an ordinary hand-supported spray nozzle, a jet of l5 to 20 meters (38 to 5l feet) may be obtained.

For carrying out the method of this invention with the apparatus described hereinabove and illustrated in the attached drawings, it is suiiicient to open the stopcock 25 of the spray nozzle 26, the stopcock 3a of the compressedgas cylinder 3 having previously been opened to permit the delivery of the ingredients under a moderate pressure in both conduits 14 and 15. Immediately as the cock 25 is opened, the two ingredients ow through the respective conduits and meet each other with a certain velocity in the space of the vessel 16 in which the chemical foam is produced as already stated hereinabove.

It may be pointed out that at the beginning of the operation of this apparatus, that is, when the vessel 16 is still empty, the velocity at which the particles of the two ingredients impinge against each other in this vessel 16 has not yet the optimum, desired value, so that the foam swelling is moderate at iirst. However, immediately as the vessel 16 becomes filled with foam, the apparatus operates under normal conditions and the jets of the two ingredients meet each other at the desired speed ranging from 4.5 m./sec. to 8 m./sec. (14.5 ft./sec. to 26 ft./sec.), thus providing an optimum reaction and a maximum swelling.

The length and diameter of the vessel 16 constituting the foam-generating chamber is determined with due consideration of the size of pipe 23, tube 24 and spray nozzle 26 to provide a proper foam-retaining delay before discharging the foam through the nozzle; under these conditions, the foam is properly hardened before being ejected, as the ingredients may continue their reaction with each other.

Due to the particular shape of the face of the deector 18 which registers with the orifices of the components 17a and 17b, this deector 1S will somewhat break up the jets of the two ingredients, thus promoting the impact between their particles at the desired speed. However, it is the essential function of this detlector to permit the desired checking or restraining of the jet of acid ingredient issuing from the central passage of the component 17a, so that the consistency of the foam generated in the vessel 16 may be regulated at will by causing the deflector 18 to change its position with respect to the oriiice in the component 17a by means of manual operation of the control knob 22. The checking action is applicable to this jet by the fact that the component 17a projects slightly into the vessel 16 towards the deector 18, and that this deector is formed with a central convex portion 18a surrounded by the annular concave portion.

The point may be emphasized that the operator may stop the production of foam at will and at any moment by simply closing the cock 25. In fact, when the cock 25 is thus closed any ilow of ingredients into the vessel 16 is discontinued immediately, so that no reaction can subsequently take place between two jets of the ingredients concerned. As the pressures are balanced, the reaction cannot take place. Moreover, the ingredients remaining in the conduits 14 and 15 and reservoirs 1 and 2 cannot mix or become altered, as the foam remaining in the vessel 116 acts as a neutralizing plug in front of the orifices of the components 17a, 17b connected to and constituting the discharge ends of the conduits 15, 14.

Under these conditions, the apparatus is ready for a subsequent use and in this case the operator has simply to open the valve 25 to resume the generation and discharge of foam as before. In hitherto known devices when one of the liquids is mixed with the other, even in small quantities, the complete mass reacts more or less and becomes useless for a subsequent operation while producing a dangerous pressure rise in the reservoir wherein the liquids are mixed or in contact with each other.

Finally, due to the specific arrangement of the foamgenerating chamber of this invention and due to the fact that this chamber is in close proximity of the spray nozzle, the foam is moved only along a relatively short path, that is, from this chamber to the outlet orifice of the nozzle. On the other hand, in conventional apparatus, wherein the foam is produced in close proximity of the reservoir and at a relatively great distance from the spray nozzle, the foam is conveyed along a relatively long path, thus causing various drawbacks. Thus, notably, due to the gradual hardening of the foam, a considerable pressure drop occurs, and pipe lines and hoses of relatively large crosssection must be used. These drawbacks are eliminated in the apparatus and by the method of this invention wherein the movement of foam is somewhat replaced by two separate movements of liquid ingredients.

What I claim as new is:

1. In a foam producing apparatus, in combination, a closed substantially cylindrical vessel having a first end and a second end; first and second conduit means having discharge ends connected to the first end of said vessel for respectively projecting into the vessel streams of a first and a second foam producing ingredient at moderate pressures and at a speed of between about 4.5.-8 m./sec., said ingredients adapted to form a chemical foam when brought into contact with each other in said vessel and the discharge end of one of said conduit means concentrically surrounding the discharge end of the other conduit means; a deflector provided in and having a deflecting surface turned toward the first end of said vessel, said deecting surface including a projecting portion arranged substantially coaxially with and facing the discharge end of said other conduit means and an annular concave portion surrounding said projecting portion and facing the discharge end of said one conduit means; adjusting means for reciprocating said deiiector in directions toward and away from the iirst end of said vessel and for thereby selectively adjusting the spacing of said deilecting surface rom the discharge ends of said conduit means, said adjusting means comprising spindle means extending through the second end of said vessel and manually operable means for moving said spindle means located externally of said vessel; and foam discharging outlet pipe means communicating with said vessel at a point adjacent to said second end thereof.

2. In a foam producing apparatus, in combination, a closed substantially cylindrical vessel having a iirst end and a second end; first and second conduit means having discharge ends connected to the rst end of said vessel for respectively projecting into the vessel streams of a first and a second foam producing ingredient at moderate pressures and at a speed of between about 4 5-8 m./sec., said ingredients adapted to form a chemical foam when brought into contact with each other in said vessel and the discharge end of one of said conduit means concentrically surrounding the discharge end of the other conduit means, the discharge end of said one conduit means formed with a plurality of orices disposed circularly about the discharge end of said other conduit means; a delector provided in and having a dellecting surface turned toward the l'irst end of said vessel, said deilecting surface including a projecting portion arranged substantially coaxially with and facing the discharge end of said other conduit means and an annular concave portion surrounding said projecting portion and facing the discharge end of said one conduit means; adjusting means for reciprocating said deflector in directions toward and away from the first end of said vessel and for thereby selectively adjusting the spacing of said deecting surface from the discharge ends of said conduit means, said adjusting means comprising spindle means extending through the second end of said vessel and manually operable means for moving said spindle means located externally of said vessel; and foam discharging outlet pipe means communicating with said vessel at a point adjacent to said second end thereof.

3. In a foam producing apparatus, in combination, a closed substantially cylindrical vessel having a first end and a second end; rst and second conduit means having discharge ends connected to the rst end of said vessel for respectively projecting into the vessel streams of an acid ingredient and of a basic ingredient at moderate pressures and at a speed of between about 4.5-8 m./sec., said ingredients adapted to form a chemical `foam when brought into contact with each other in said vessel, and the discharge end of said second conduit means concentrically surrounding the discharge end of said rst conduit means; a dellector provided in and having a deecting surface turned toward the lirst end of said vessel, said deecting surface including a projecting portion arranged substantially coaxially with and facing the discharge end of said first conduit means and an annular concave portion surrounding said projecting portion and facing the discharge end of said second conduit means, the discharge end of said first conduit means extending beyond the discharge end of said second conduit means whereby the acid 8 ingredient is projected against said projecting portion from a point closer to said deilecting surface than the point from which the basic ingredient is projected against said annular concave portion; adjusting means for reciprocating said deflector and for thereby selectively adjusting the spacing of said deflecting surface from the discharge ends of said conduit means, said adjusting means comprising spindle means extending through the second `end of said vessel and manually operable means for moving said spindle means located externally of said vessel; and foam discharging outlet pipe means communicating with said vessel at a point adjacent to the second end thereof.

References Cited in the file of this patent UNITED STATES PATENTS 

